Grades validation do not include CS and CU for modules with only those grades

[nus-se-script]

Problem

Grades validation do not include CS and CU for modules such as CFG1002 which only has those grades and not grades like A, A- etc.

Steps to reproduce

Using these commands:

1. add 00000000 n/Devin Wang e/2847devin293wang3@mail.sg p/84950293 c/mycourse r/student a/1234 Yishun Road, #13-24, Yishun View, Singapore 630234
2. module 00000000 m/CFG1002
3. grade 00000000 m/cfg1002 g/CS The actual output will be as seen in the following image, where the CS grade is not accepted:

   Expected

   Maybe we could have tweaked it to get the expected output where CS and CU are accepted as well

   Severity Label Explanation

   The chosen severity label is severity.Medium as it give a major inconvenience and prevent grading for course instructors from modules such as CFG1002 that can only have the CS and CU grades.

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_{[original: nus-cs2103-AY2425S1/pe-interim#1838] [original labels: severity.Medium type.FeatureFlaw]}

[ethan-goh]

Team's Response

Duplicate of #1962.

Duplicate status (if any):

Duplicate of #1962